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200 lines
5.1 KiB
JavaScript

;(function( win, $ ) {
function featureTest( property, value, noPrefixes ) {
// Thanks Modernizr! https://github.com/phistuck/Modernizr/commit/3fb7217f5f8274e2f11fe6cfeda7cfaf9948a1f5
var prop = property + ':',
el = document.createElement( 'test' ),
mStyle = el.style;
if( !noPrefixes ) {
mStyle.cssText = prop + [ '-webkit-', '-moz-', '-ms-', '-o-', '' ].join( value + ';' + prop ) + value + ';';
} else {
mStyle.cssText = prop + value;
}
return mStyle[ property ].indexOf( value ) !== -1;
}
function getPx( unit ) {
return parseInt( unit, 10 ) || 0;
}
var uniqueIdCounter = 0;
var S = {
classes: {
plugin: 'fixedsticky',
active: 'fixedsticky-on',
inactive: 'fixedsticky-off',
clone: 'fixedsticky-dummy',
withoutFixedFixed: 'fixedsticky-withoutfixedfixed'
},
keys: {
offset: 'fixedStickyOffset',
position: 'fixedStickyPosition',
id: 'fixedStickyId'
},
tests: {
sticky: featureTest( 'position', 'sticky' ),
fixed: featureTest( 'position', 'fixed', true )
},
// Thanks jQuery!
getScrollTop: function() {
var prop = 'pageYOffset',
method = 'scrollTop';
return win ? (prop in win) ? win[ prop ] :
win.document.documentElement[ method ] :
win.document.body[ method ];
},
bypass: function() {
// Check native sticky, check fixed and if fixed-fixed is also included on the page and is supported
return ( S.tests.sticky && !S.optOut ) ||
!S.tests.fixed ||
win.FixedFixed && !$( win.document.documentElement ).hasClass( 'fixed-supported' );
},
update: function( el ) {
if( !el.offsetWidth ) { return; }
var $el = $( el ),
height = $el.outerHeight(),
initialOffset = $el.data( S.keys.offset ),
scroll = S.getScrollTop(),
isAlreadyOn = $el.is( '.' + S.classes.active ),
toggle = function( turnOn ) {
$el[ turnOn ? 'addClass' : 'removeClass' ]( S.classes.active )
[ !turnOn ? 'addClass' : 'removeClass' ]( S.classes.inactive );
},
viewportHeight = $( window ).height(),
position = $el.data( S.keys.position ),
skipSettingToFixed,
elTop,
elBottom,
$parent = $el.parent(),
parentOffset = $parent.offset().top,
parentHeight = $parent.outerHeight();
if( initialOffset === undefined ) {
initialOffset = $el.offset().top;
$el.data( S.keys.offset, initialOffset );
$el.after( $( '<div>' ).addClass( S.classes.clone ).height( height ) );
}
if( !position ) {
// Some browsers require fixed/absolute to report accurate top/left values.
skipSettingToFixed = $el.css( 'top' ) !== 'auto' || $el.css( 'bottom' ) !== 'auto';
if( !skipSettingToFixed ) {
$el.css( 'position', 'fixed' );
}
position = {
top: $el.css( 'top' ) !== 'auto',
bottom: $el.css( 'bottom' ) !== 'auto'
};
if( !skipSettingToFixed ) {
$el.css( 'position', '' );
}
$el.data( S.keys.position, position );
}
function isFixedToTop() {
var offsetTop = scroll + elTop;
// Initial Offset Top
return initialOffset < offsetTop &&
// Container Bottom
offsetTop + height <= parentOffset + parentHeight;
}
function isFixedToBottom() {
// Initial Offset Top + Height
return initialOffset + ( height || 0 ) > scroll + viewportHeight - elBottom &&
// Container Top
scroll + viewportHeight - elBottom >= parentOffset + ( height || 0 );
}
elTop = getPx( $el.css( 'top' ) );
elBottom = getPx( $el.css( 'bottom' ) );
if( position.top && isFixedToTop() || position.bottom && isFixedToBottom() ) {
if( !isAlreadyOn ) {
toggle( true );
sidebarOn();
}
} else {
if( isAlreadyOn ) {
toggle( false );
sidebarOff();
}
}
},
destroy: function( el ) {
var $el = $( el );
if (S.bypass()) {
return $el;
}
return $el.each(function() {
var $this = $( this );
var id = $this.data( S.keys.id );
$( win ).unbind( '.fixedsticky' + id );
$this
.removeData( [ S.keys.offset, S.keys.position, S.keys.id ] )
.removeClass( S.classes.active )
.removeClass( S.classes.inactive )
.next( '.' + S.classes.clone ).remove();
});
},
init: function( el ) {
var $el = $( el );
if( S.bypass() ) {
return $el;
}
return $el.each(function() {
var _this = this;
var id = uniqueIdCounter++;
$( this ).data( S.keys.id, id );
$( win ).bind( 'scroll.fixedsticky' + id, function() {
S.update( _this );
}).trigger( 'scroll.fixedsticky' + id );
$( win ).bind( 'resize.fixedsticky' + id , function() {
if( $el.is( '.' + S.classes.active ) ) {
S.update( _this );
}
});
});
}
};
win.FixedSticky = S;
// Plugin
$.fn.fixedsticky = function( method ) {
if ( typeof S[ method ] === 'function') {
return S[ method ].call( S, this);
} else if ( typeof method === 'object' || ! method ) {
return S.init.call( S, this );
} else {
throw new Error( 'Method `' + method + '` does not exist on jQuery.fixedsticky' );
}
};
// Add fallback when fixed-fixed is not available.
if( !win.FixedFixed ) {
$( win.document.documentElement ).addClass( S.classes.withoutFixedFixed );
}
})( window, jQuery );
// FixedSticky.tests.sticky = false;